In recent years, a treatment using a catheter is provided for an aneurysm, or clogging of cerebral blood vessels, under X-ray fluoroscopy by an X-ray diagnostic apparatus in some cases. Such intravascular treatment using a catheter is called IVR (interventional radiology).
On the other hand, the X-ray absorption amount changes depending on the portion of a patient. For example, the absorption amount of a portion such as a crystalline lens (eye) or thyroid is high. The X-ray conditions of IVR are determined to acquire information necessary for a catheter method. That is, the X-ray conditions of IVR do not consider the fact that the absorption amount changes depending on each portion. Under the X-ray conditions which define a long fluoroscopy time, a high sensitivity portion such as an eye or thyroid may be exposed at a high dose.
On the other hand, for an X-ray diagnostic apparatus, there are known a technique of reducing an exposure dose by inserting a compensation filter such as a metal plate into an arbitrary irradiation field to attenuate X-rays, and a technique of preventing exposure by inserting a collimator such as a lead plate into an arbitrary irradiation field to block X-rays.
The above-described X-ray diagnostic apparatus, however, requires manual operation of a compensation filter and collimator. Therefore, the exposure dose of a high sensitivity portion within an X-ray irradiation range is not automatically reduced. In particular, the compensation filter is originally a filter used to prevent halation, and is thus not automatically used to reduce the exposure dose.
It is, however, desirable for the X-ray diagnostic apparatus to automatically reduce the exposure dose of a high sensitivity portion of a patient. In addition to a high sensitivity portion of the patient, it is desirable to reduce the exposure dose of a portion such as the hand of a technician at the time of paracentesis and the hand of an assistant at the time of PPI (Percutaneous Peripheral Intervention). In summary, an X-ray diagnostic apparatus which can automatically reduce the exposure dose of a high sensitivity portion of a patient and that of an exposure dose reduction target portion such as the hand of a technician or assistant is required.
It is an object to provide an X-ray diagnostic apparatus which can automatically reduce the exposure dose of an exposure dose reduction target portion.